There has been a growing interest in manufacturing commodity chemicals using renewable biological materials as feedstock. For example, biocatalysts have been developed to manufacture succinic acid, lactic acid, 3-hydroxypropionic acid, 1,3-propanediol, 1,4-butanediol and butanol using biological feedstock such as glucose, glycerol, sucrose and cellulosic hydrolysates. The commodity chemicals thus derived from biological materials can be used in a number chemical industries as a drop-in substitute for raw materials currently derived from petrochemical feedstock. The present invention provides novel methods for manufacturing bio-acrylic acid, bio-1,4-butanediol and bio-acrylonitrile using biomass-derived 1,3-propanediol which is currently manufactured at commercial scale in a cost-effective way using biological feedstock.
Acrylic acid and its esters are important commodity chemicals used in the production of polyacrylic esters, elastomers, superabsorbent polymers, floor polishes, adhesives, paints, and the like. Historically, acrylic acid has been produced by hydroxycarboxylation of acetylene. This method utilizes nickel carbonyl and high pressure carbon monoxide, both of which are expensive and considered environmentally unfriendly. Other methods, e.g., those utilizing ethenone and ethylene cyanohydrins as the raw materials, generally have the same pitfalls. BASF (Germany), Dow Chemicals (USA), Arkema (France), and Nippon Shokubai (Japan) are using propylene as the raw material for acrylic acid manufacturing.
There is a growing interest in manufacturing bio-acrylic acid using renewable resources. Lactic acid and 3-hydroxypropionic acid derived from biological fermentation of carbohydrates are considered to be ideal raw material for manufacturing acrylic acid through vapor-phase dehydration reaction mediated by chemical catalysts. The process conditions for deriving acrylic acid from lactic acid and 3-hydroxypropionic acid are being worked out and are far from reaching commercial scale manufacturing. Dow Chemicals has partnered with OPXBio to develop bioacrylic acid using 3-hydroxypropionic acid derived from the fermentation of sugars. BASF is also collaborating with Novozymes A/S and Cargill Inc. to manufacture bio-acrylic acid using fermentation-derived 3-hydroxypropionic acid as the starting material. Myriant Corporation and Procter & Gamble are also independently developing a process involving vapor phase dehydroxylation of biomass-derived lactic acid. Metabolix is attempting to manufacture bio-acrylic acid using its FAST (fast acting selective thermolysis) process. Genomatica has developed a novel method for bio-acrylic acid manufacturing using fumaric acid derived from fermentation process. Genomatica technology utilizes ethylene and fumaric acid to perform metathesis reaction to produce acrylic acid. These various current approaches for manufacturing bio-acrylic acid are not yet cost competitive to propylene-based acrylic acid manufacturing and involves recovery steps which is expected to contribute to high capital cost and operational cost. Thus there is a need for additional cost-effective methods for manufacturing biomass-derived acrylic acid and its esters at commercial scale. This present invention provides a simple two-step scalable process for manufacturing bio-acrylic acid using biomass-derived 1,3-propanediol.
Succinic acid derived from biological feedstock such as glucose, sucrose, glycerol and cellulosic hydrolysates is being considered as a suitable drop-in feedstock in the manufacture of useful industrial chemicals such as 1,4-butanediol (BDO), gamma-butryolactone (GBL) and tetrahydrofuran (THF). BDO is currently used as an industrial solvent in the manufacture of plastics and polyesters and is a precursor to useful chemicals like GBL and THF. It is a protic polar solvent, which is miscible with water. The global market for BDO is about 3 billion pounds per year, almost exclusively produced from petrochemical processes. GBL is suitable as a solvent, to replace environmentally harmful chlorinated solvents, in the preparation of pyrrolidones used as a raw material in the manufacture of herbicides, rubber additives, and pharmaceuticals, and in the production of biodegradable polymers. THF is an aprotic, water miscible solvent used in organic chemistry. It is also widely used in the production of resins and polymers.
The typical process to produce BDO starts from petrochemical-derived acetylene which is reacted with formaldehyde using Reppe chemistry. The resulting 1, 4-butynediol is then hydrogenated to form BDO. There are several other chemical routes to synthesize BDO, but one of the most economical routes starts from butane as a raw material. First, butane is oxidized to produce maleic anhydride. Then maleic anhydride can be converted to BDO via the BP/Lurgi Geminox process or the Davy Technology Process. The former process recovers maleic anhydride as maleic acid and performs liquid-phase hydrogenation to produce a mixture of BDO with THF and/or GBL. In the Davy Technology Process, maleic anhydride is esterified to dimethyl maleate, which is then vaporized and fed to a vapor-phase hydrogenation system to produce dimethyl succinate. Dimethyl succinate undergoes hydrogenolysis reaction to produce GBL and BDO, which can be further converted into THF. These products are separated by distillation and methanol is recycled back to the esterification reactor.
The conventional process for producing BDO, GBL, and THF is not a sustainable process, since the raw material is derived from petrochemical feedstock. One of the possible pathways to produce bio-BDO is by esterifying the bio-succinic acid to dialkyl succinate, followed by a hydrogenation step to produce BDO, GBL, and THF. Another approach that has been followed to manufacture bio-BDO is to engineer a microbial organism capable of producing bio-BDO as a fermentation product (Burk, Int. Sugar J. 112, 1333 (2010); McGrew, Specialty Chem Mag. July 2010, pp 32-34; Yim et al., Nature Chem Bio. 7, 445 (2011)). U.S. Pat. Nos. 7,858,350 and 8,129,156 provides microorganism for the production of 1,4-butanediol. U.S. Pat. No. 8,067,214 provides composition and methods for the biosynthesis of 1,4-butanediol and its precursors. U.S. Pat. No. 8,129,169 provides microorganisms for the production of 1,4-butanediol and related methods. U.S. Pat. No. 7,947,483 provides methods and organisms for the growth coupled production of 1,4-butanediol. U.S. Pat. No. 8,715,971 provides microorganisms and method for the coproduction of isopropanal and 1,4-butanediol. U.S. Pat. No. 8,530,210 provides microorganisms and methods for the coproduction of 1,4-butanediol and gamma-butryolactone. U.S. Pat. No. 8,597,918 provides a process for separating 1,4-butanediol from a fermentation broth. The present invention provides yet another novel and cost-effective method for producing bio-BDO using biomass-derived 1,3-propanediol as the starting material.
Acrylonitrile is yet another commodity chemical that can be manufactured according to the present invention using biomass-derived 1,3-propanediol as the starting material. Acrylonitrile is widely used in large quantities in a number of commercial products and processes, notably in clothing and plastics. It is used in the production of many different synthetic polymers (ABS—Acrylonitrile butadiene styrene; ASA—Acrylonitrile styrene acrylate; NBR—Nitrile butadiene rubber; and SAN—Styrene acrylonitrile). ABS is used in everything from children's LEGO toys to golf club heads and car parts. NBR is probably most identifiable in non-latex gloves, but is also used in synthetic leather, gaskets, and seals. SAN is most commonly found in kitchen products because of its higher tolerance for heat. Furthermore, acrylonitrile is industrially used as a starting reagent for the production of acrylic acid. Currently acrylonitrile is obtained from propylene through oxidation reaction using bismuthphosphomolybdate catalyst. Propylene used in the manufacture of acrylonitrile is derived as a byproduct of petroleum and natural gas refining. There is a need to produce bio-based acrylonitrile from renewable resources. The present invention provides a novel method for manufacturing bio-acrylonitrile using biomass-derived 1,3-propanediol as the starting material.